Easiest and most correct way of creating as building volume from imported cad lines

Having trouble making the most simple building volume from imported cad lines (z information)
The problem is that the the cad lines don’t always join. I’ve have tried to move some of them but the risk of messing things up is bigger than actual working forward

This is the method I have been using:

1 Using the Cad lines together with surface from 3 och 4 corners Don’t know it this is the most efficient way.
2 extend the surface so that corners overlap
3 CreateSolid (sometimes it doesn’t create a solid

The main problem I have is that the corners don’t add up/are clean

I’ve also tried to use intersect to see were things intersect and move them to the correct position but i end up messing things up more. And there is alot of lines and volumes.

part of model:
simplifiedsolidfromcadlines.3dm (360.5 KB)

Hi, the file is pretty messy, I would suggest to use those curves only as reference and draw the new ones on top of them.
in several cases using Rhino, starting from scratch is the easiest, fastest, cleanest way to solve a problem like this.